Evaluation of bioremediation performance and microbial population dynamics of TPH-contaminated soil

• Main Authors: Li-hsin Chang, 張儷馨
• Other Authors: Liang-Ming Whang
• Format: Others
• Language: zh-TW
• Published: 2008
• Online Access: http://ndltd.ncl.edu.tw/handle/98835949763413088231

碩士 === 國立成功大學 === 環境工程學系碩博士班 === 96 === Oil pollution in soil became more and more seriously due to the discharge of oil extraction wastewater and oil-contained solid wastes, and there were 642 pollution sites announced nowadays in Taiwan. Bioremediation is an economical and ‘green’ solution to the problem of oil pollution. In previous studies in our lab, we utilized low polluted soil with adding extra oil to mimic the condition of TPH degradation in nature. In this study, to investigate that whether past experiments could response to the real condition of TPH degradation, we used batch tests to simulate ex situ land farming for TPH degradation in polluted long soil and low polluted soil added extra oil to find the role of time as soil polluted in TPH degradation. In our results, as operating batch tests for 118 days the average total removal up to 57% in polluted long soil and 76% in low polluted soil with adding extra oil, and the first stage reaction rate constant was -0.0196 day-1 and -0.0253 day-1. Consequently, the efficiency of TPH degradation decreased with time after the soil was polluted and the results in experiment of low polluted soil with adding extra oil were not enough to stimulate the actual condition of TPH degradation. In order to mimic the condition of TPH degradation in polluted soil naturally, we tried to utilize another soil sample with low concentration of microbes to find the efficiency of TPH degradation in that after the treatment of biostimulation and bioaugmentation. As operating batch tests for 126 days the average total removal up to 81% in soil after treatment of biostimulation , and the first stage reaction rate constant was -0.0414 day-1. After the treatment of bioaugmentation by adding diesel-eliminating strains KH1 and kitchen wastes performed the best removal of TPH and the second stage reaction rate constant of them was -0.0124 day-1 and -0.0119 day-1. Therefore we supposed that the operating process in TPH polluted soil would be biostimulation of adding suitable nutrients in the first and subsequently the treatment of bioaugmentation by adding diesel-eliminating strains KH1 and kitchen wastes could reduce the required time of biodegradation. Simultaneously we tried to detect the changes of microorganisms in batch tests by terminal restriction fragment length polymorphism (T-RFLP).We found that the major fragments were at 123bp, 213bp, and 514bp in the TPH rapid degradation phase, and corresponding with other batch tests. Thus, we could understand the changes of microorganisms in polluted soil as degradation of TPH by T-RFLP diagram to find the dominant strains in biodegradation process. Finally, in order to understand the relationship between the variables of batch and microbial population variation, we carried multivariate statistical analysis out to analyze the data of T-RFLP diagram. We considered that there results would provide us the related information to help the efficiency of TPH degradation. We demonstrated that the relationship in time as soil polluted in TPH degradation, the time of the biodegradation, pollutants properties and the efficiency of TPH degradation in the results of multivariate statistical analysis. While we proceeded to choose the treatment of unknown polluted soils in the future, we should investigate into these three variables to provide us the important information of estimating the time required for treatment.